Academic literature on the topic 'Microorganisms – Motility'
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Journal articles on the topic "Microorganisms – Motility"
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Petit, M. D. A., U. Velden, A. J. Winkelhoff, and J. Graaff. "Preserving the motility of microorganisms." Oral Microbiology and Immunology 6, no. 2 (April 1991): 107–10. http://dx.doi.org/10.1111/j.1399-302x.1991.tb00460.x.
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Mehdizadeh Allaf, Malihe, and Hassan Peerhossaini. "Cyanobacteria: Model Microorganisms and Beyond." Microorganisms 10, no. 4 (March 24, 2022): 696. http://dx.doi.org/10.3390/microorganisms10040696.
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In this review, the general background is provided on cyanobacteria, including morphology, cell membrane structure, and their photosynthesis pathway. The presence of cyanobacteria in nature, and their industrial applications are discussed, and their production of secondary metabolites are explained. Biofilm formation, as a common feature of microorganisms, is detailed and the role of cell diffusion in bacterial colonization is described. Then, the discussion is narrowed down to cyanobacterium Synechocystis, as a lab model microorganism. In this relation, the morphology of Synechocystis is discussed and its different elements are detailed. Type IV pili, the complex multi-protein apparatus for motility and cell-cell adhesion in Synechocystis is described and the underlying function of its different elements is detailed. The phototaxis behavior of the cells, in response to homogenous or directional illumination, is reported and its relation to the run and tumble statistics of the cells is emphasized. In Synechocystis suspensions, there may exist a reciprocal interaction between the cell and the carrying fluid. The effects of shear flow on the growth, doubling per day, biomass production, pigments, and lipid production of Synechocystis are reported. Reciprocally, the effects of Synechocystis presence and its motility on the rheological properties of cell suspensions are addressed. This review only takes up the general grounds of cyanobacteria and does not get into the detailed biological aspects per se. Thus, it is substantially more comprehensive in that sense than other reviews that have been published in the last two decades. It is also written not only for the researchers in the field, but for those in physics and engineering, who may find it interesting, useful, and related to their own research.
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Grassi, Hilda Cristina, Efrén De Jesús Andrades, María Lorena Lobo, and Jesús Enrique Andrades. "A prototype biospecklemeter for microbiological analysis: a starting point for a potential digital-image laser antibiotic susceptibility test." Laser Physics 32, no. 9 (September 1, 2022): 095604. http://dx.doi.org/10.1088/1555-6611/ac8677.
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Abstract This work describes the design and construction of a low-cost prototype biospecklemeter. In this first report of its applications a microbiological analysis was performed. The relationship between microorganism density, motility and biospeckle activity was evaluated. The aim is to produce a device for research and for student use. The biospecklemeter was constructed on an antivibration table with low-cost materials and accessories and assayed using different microorganisms grown in Mueller–Hinton broth and/or agar as well as urine samples. Three lasers were installed (blue, green and red) as well as two webcams and a charge-coupled device camera. The samples were carried within the wells of a VDRL plate and 5–30 s videos or photographs of reflected light were taken. Video or photo processing was carried out using the method of temporal differences (ImageJ) or generalized differences (ImageDP). It was possible to establish a direct relationship between spectrophotometric absorption, the microbial count and the biospeckle intensity; changes in motility and the effect of antibiotics on bacterial laboratory samples as well as on urine samples were also detected. Finally, with this method colonies of different microorganisms on Mueller–Hinton agar were studied.
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Martínez, Asunción, Sandra Torello, and Roberto Kolter. "Sliding Motility in Mycobacteria." Journal of Bacteriology 181, no. 23 (December 1, 1999): 7331–38. http://dx.doi.org/10.1128/jb.181.23.7331-7338.1999.
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ABSTRACT Mycobacteria are nonflagellated gram-positive microorganisms. Previously thought to be nonmotile, we show here thatMycobacterium smegmatis can spread on the surface of growth medium by a sliding mechanism. M. smegmatis spreads as a monolayer of cells which are arranged in pseudofilaments by close cell-to-cell contacts, predominantly along their longitudinal axis. The monolayer moves away from the inoculation point as a unit with only minor rearrangements. No extracellular structures such as pili or fimbriae appear to be involved in this process. The ability to translocate over the surface correlates with the presence of glycopeptidolipids, a mycobacterium-specific class of amphiphilic molecules located in the outermost layer of the cell envelope. We present evidence that surface motility is not restricted to M. smegmatis but is also a property of the slow-growing opportunistic pathogen M. avium. This form of motility could play an important role in surface colonization by mycobacteria in the environment as well as in the host.
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Varshney, Rohit, Arshdeep Kaur Gill, Mujeeb Alam, Chinmayee Agashe, and Debabrata Patra. "Fluid actuation and buoyancy driven oscillation by enzyme-immobilized microfluidic microcapsules." Lab on a Chip 21, no. 22 (2021): 4352–56. http://dx.doi.org/10.1039/d1lc00699a.
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To mimic the life-like complex behavior of microorganisms, enzyme-immobilized microfluidic microcapsules were fabricated to demonstrate the enzyme powered fluid actuation and buoyancy driven motility.
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Sarbu, Ionela, Tatiana Vassu, Mariana Carmen Chifiriuc, Marcela Bucur, Ileana Stoica, Petrut Stefana, Elena Rusu, Horatiu Moldovan, and Diana Pelinescu. "Assessment the Activity of Some Enzymes and Antibiotic Substances Sensitivity on Pathogenic Bacteria Species." Revista de Chimie 68, no. 12 (January 15, 2018): 3015–21. http://dx.doi.org/10.37358/rc.17.12.6029.
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Microbial and opportunistic pathogens cause serious problem to human host by releasing different compounds which are involved in colonization, invasion or in alteration of immune process. In this study we propose ourselves to analyze the virulence profile of microorganisms involved in urinary tract infections and bacterial vaginosis in order to compare the virulence mechanisms developed by these microorganisms. We assessed the virulence profile (motility, adhesion to HeLa cell line, biofilm formation, production of enzymes, antibiotic susceptibility) using phenotypic methods. The microbial strains isolated from urinary tract infections present a high ability to release amylases, caseinase, siderophore-like, half of them have present high motility and also were highly resistant to antibiotics, while the microbial strains isolated from bacterial vaginosis present a high ability to bind human epithelial cells and to release hemolyzin and DN-ase.
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Sidorova, Daria E., Mariia I. Skripka, Inessa A. Khmel, Olga A. Koksharova, and Vladimir A. Plyuta. "Effects of Volatile Organic Compounds on Biofilms and Swimming Motility of Agrobacterium tumefaciens." Microorganisms 10, no. 8 (July 26, 2022): 1512. http://dx.doi.org/10.3390/microorganisms10081512.
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Volatile organic compounds (VOCs) emitted by bacteria play an important role in the interaction between microorganisms and other organisms. They can inhibit the growth of phytopathogenic microorganisms, modulate plant growth, and serve as infochemicals. Here, we investigated the effects of ketones, alcohols, and terpenes on the colony biofilms of plant pathogenic Agrobacterium tumefaciens strains and swimming motility, which can play an important role in the formation of biofilms. It was shown that 2-octanone had the greatest inhibitory effect on biofilm formation, acting in a small amount (38.7 g/m3). Ketone 2-butanone and unsaturated ketone β-ionone reduced the formation of biofilms at higher doses (145.2–580.6 and 387.1–1548.3 g/m3, respectively, up to 2.5–5 times). Isoamyl alcohol and 2-phenylethanol decreased the formation of biofilms at doses of 88.7 and 122.9 g/m3 by 1.7 and 5 times, respectively, with an increased effect at 177.4 and 245.9 g/m3, respectively. The agrobacteria cells in mature biofilms were more resistant to the action of ketones and alcohols. These VOCs also suppressed the swimming motility of agrobacteria; the radius of swimming zones decreased ~from 2 to 5 times. Terpenes (−)-limonene and (+)-α-pinene had no significant influence on the colony biofilms and swimming motility at the doses used. The results obtained represent new information about the effect of VOCs on biofilms and the motility of bacteria.
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Scherr, Thomas, Chunliang Wu, W. Todd Monroe, and Krishnaswamy Nandakumar. "Computational fluid dynamics as a tool to understand the motility of microorganisms." Computers & Fluids 114 (July 2015): 274–83. http://dx.doi.org/10.1016/j.compfluid.2015.03.012.
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Acres, Jacqueline, and Jay Nadeau. "2D vs 3D tracking in bacterial motility analysis." AIMS Biophysics 8, no. 4 (2021): 385–99. http://dx.doi.org/10.3934/biophy.2021030.
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<abstract> <p>Digital holographic microscopy provides the ability to observe throughout a large volume without refocusing. This capability enables simultaneous observations of large numbers of microorganisms swimming in an essentially unconstrained fashion. However, computational tools for tracking large 4D datasets remain lacking. In this paper, we examine the errors introduced by tracking bacterial motion as 2D projections vs. 3D volumes under different circumstances: bacteria free in liquid media and bacteria near a glass surface. We find that while XYZ speeds are generally equal to or larger than XY speeds, they are still within empirical uncertainties. Additionally, when studying dynamic surface behavior, the Z coordinate cannot be neglected.</p> </abstract>
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Klimenko, A. I., and S. A. Lashin. "MODELING CHANGES IN THE ADAPTABILITY AND MOTILITY OF MICROORGANISMS IN CHANGING AQUATIC ECOSYSTEMS." http://eng.biomos.ru/conference/articles.htm 1, no. 19 (2021): 203–4. http://dx.doi.org/10.37747/2312-640x-2021-19-203-204.
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The results of our simulations show that motile forms (as opposed to sedentary forms) have an advantage under nutrient-poor conditions corresponding to the environment in which marine bacteria live. There is a turning point in the magnitude of the migration penalty that determines whether the Nomadic strategy will be successful or not.
Dissertations / Theses on the topic "Microorganisms – Motility"
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Brumley, Douglas Richard. "Hydrodynamics of swimming microorganisms." Thesis, University of Cambridge, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.608174.
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Bennett, Rachel R. "Physics of microorganism behaviour : motility, synchronisation, run-and-tumble, phototaxis." Thesis, University of Oxford, 2015. http://ora.ox.ac.uk/objects/uuid:accc7f3c-b472-4bb9-b821-59725a54ccb7.
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Microorganisms have evolved in a low Reynolds number environment and have adapted their behaviour to its viscosity. Here, we consider some features of behaviour observed in microorganisms and use hydrodynamic models to show that these behaviours emerge from physical interactions, including hydrodynamic friction, hydrodynamic interactions and mechanical constraints. Swimming behaviour is affected by surfaces and observations of Vibrio cholerae show that it swims near a surface with two distinct motility modes. We develop a model which shows that friction between pili and the surface gives the two motility modes. The model is extended to study the behaviour of bacteria which are partially attached to a surface. Observations of Shewanella constrained by a surface show several different behaviours. The model shows that different degrees of surface constraint lead to different types of behaviour; the flexibility of the flagellar hook and the torque exerted by the flagellar motor also cause different behaviours. Near surface behaviour is important for understanding the initial stages of biofilm formation. Chlamydomonas swims using synchronous beating of its two flagella. A simple model of Chlamydomonas is developed to study motility and synchronisation. This model shows that the stability of synchronisation is sensitive to the beat pattern. Run-and-tumble behaviour emerges when we include intrinsic noise, without the need for biochemical signalling. The model is also used to show how observed responses of the flagella to light stimuli produce phototaxis. Finally we study hydrodynamic synchronisation of many cilia and consider the stability of metachronal waves in arrays of hydrodynamically coupled cilia. This thesis shows that physical interactions are responsible for many behavioural features and that physical models provide a useful technique for exploring open questions in biology.
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Fadlallah, Hadi. "Effects of hydrodynamic stress on microorganisms in photobioreactors for biofuel production." Thesis, Sorbonne Paris Cité, 2016. http://www.theses.fr/2016USPCC281/document.
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Dans la crise énergétique mondiale actuelle, la demande de production d'énergie reposant sur des sources renouvelables est en hausse. Les biocarburants offrent une option intéressante pour cette transition énergétique. Les intérêts dans le développement d'une troisième génération de biocarburants produits à partir de microalgues et de cyanobactéries ont nettement augmenté. Ainsi, la conception et la construction des systèmes de culture qui fonctionnent dans des conditions optimales sont nécessaires pour bénéficier au maximum du contenu énergétique de ces espèces. Les photobioréacteurs (PBRs) sont des systèmes qui offrent un bon contrôle sur les conditions de culture et de la croissance.Les effets du stress hydrodynamique sur la croissance ainsi que sur la motilité de deux espèces de microorganismes, la cyanobactérie Synechocystis et la microalgue Chlamydomonas reinhardtii, sont étudiés dans deux types de PBR: cuve agitée (agitation mécanique) et airlift tubulaire (agitation par des bulles ascendantes). Les résultats ont montré que Synechocystis est très résistant au cisaillement; la variation de son taux de croissance exponentiel est limitée à la décomposition des colonies cellulaires, alors que sa capacité porteuse semble augmenter avec le cisaillement jusqu'à une valeur maximale. D'autre part, C. reinhardtii se montre plus sensible; son taux de croissance exponentiel augmente avec l'intensité du cisaillement, alors que sa capacité porteuse semble être moins affectée. Un modèle logistique comportant deux paramètres de croissance, le taux de croissance exponentiel et la capacité porteuse, est proposé pour décrire la croissance avec le temps. En suivant une approche de systémiques dynamiques, il a été expérimentalement montré que le taux de croissance instantanée et le taux de croissance per capita tendent vers zéro et oscillent autour d'un point fixe stable où la densité de la population atteint la capacité maximale du système.Un autre aspect de ce travail est d'étudier la motilité des deux microorganismes au cours de leurs cycles de croissance lorsqu’ils sont soumis aux différents niveaux de contrainte de cisaillement. La vitesse moyenne de nage est déterminée pendant la croissance pour des différentes valeurs de cisaillement. Les résultats ont montré que la motilité de C. reinhardtii suit trois phases différentes; une phase ascendante qui commence au milieu de la phase exponentielle de croissance, une phase descendante et enfin une phase amortie au cours de la phase stationnaire de croissance. Il a été montré que l'agitation augmente l'amplitude de la vitesse moyenne de nage et qu’elle avance la motilité cellulaire. En outre, une intensité de cisaillement élevée a conduit à un amortissement plus rapide de la vitesse moyenne vers sa valeur finale en phase stationnaire de croissance. Pour Synechocystis, la motilité n'a pas suivi une tendance claire avec le temps. Cependant, il semble que la vitesse maximale se produit toujours au milieu de la phase exponentielle de croissanceUnder the current global energy crisis, the demand of energy production relying on renewable sources has become a global need. Biofuels offer a transition towards a world of renewable energy supply and production. The interests in developing a third generation of biofuels produced from microalgae and cyanobacteria have clearly increased. Thus, the design and construction of a convenient culturing system under optimal conditions is necessary to benefit from the energy content of these species. Photobioreactors (PBRs) offer a good control over culture conditions and growth.This work investigates the effects of shear stress, generated by stirring in agitated PBRs and bubbling in airlift PBRs, on the growth and motility of two species of microorganisms, the cyanobacterium Synechocystis and the microalgae Chlamydomonas reinhardtii. The results show that Synechocystis is highly resistant to shear stress; the variation in exponential growth rate is limited to the breakdown of cellular colonies, while the carrying capacity appears to increase as a function of shear stress up to a maximal value. On the other hand, C. reinhardtii shows to be more sensitive; the exponential growth rate increases with shear stress intensity, while the carrying capacity seems to be less affected. A logistic growth model featuring two growth parameters, the exponential growth rate and the carrying capacity, is proposed to describe the growth with time. From a point of view of dynamical system approach, it is experimentally shown that the population’s instantaneous growth rate and the growth rate per capita tends to zero and converges around a stable fixed point once the population’s density reaches the carrying capacity of the growth system.Another aspect of this work is studying the motility of the two microorganisms during their growth cycle when different levels of shear stress are applied on them. The average swimming velocity is determined as a function of growth cycle for different shear stress intensities. The results show that the motility of C. reinhardtii follows three different phases; a rising phase starting in the middle of the exponential growth phase, a decay phase and finally a damped phase during the stationary growth phase. It is shown that agitation increases the magnitude of the average velocity and advances the cellular motility. Besides, high intensity in the applied shear stress led to an increase in the damping of the average velocity implying a quicker decay to the limit value at the end of the growth. For Synechocystis, the average velocity did not follow a defined pattern with time. However, it seems that the peak of the velocity occurs always in the middle of exponential phase
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Fauquenoy, Sylvain. "Implication de la N-glycosylation dans les mécanismes de motilité et d’invasion des cellules hôtes chez Toxoplasma gondii." Thesis, Lille 1, 2010. http://www.theses.fr/2010LIL10098/document.
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Toxoplasma gondii est un parasite protozoaire unicellulaire qui se développe à l’intérieur d’une cellule hôte. Chez les parasites Apicomplexa, peu de chose sont connues sur la N-glycosylation. Nous avons mis en évidence la présence de N-glycannes parasitaires totaux et démontré que ces N-glycannes sont de type riche en mannose. En utilisant une lectine, nous avons purifié de nombreuses N-glycoprotéines parasitaires intervenant majoritairement dans les mécanismes de motilité, d’invasion et de trafic intracellulaire. Nous avons démontré qu’un traitement par une drogue inhibant la synthèse des N-glycannes perturbe plusieurs processus biologiques. Nous avons étudié les fonctions biologiques des N-glycannes de TgGAP50 qui appartient au glidéosome, un moteur impliqué dans la motilité du parasite. Nous avons déterminé que TgGAP50 porte des N-glycannes hétérogènes riches en mannoses. Nous avons montré que la N-glycosylation de TgGAP50 est impliquée dans le trafic de la protéine et dans l’interaction avec les partenaires du glidéosome. Nos travaux démontrent que T. gondii est capable de synthétiser des N-glycoprotéines et que les N-glycannes sont potentiellement impliqués dans le trafic des protéines et dans les interactions moléculaires importantes pour la motilité et l’invasion des cellules hôtes par le parasiteThe apicomplexan parasite Toxoplasma gondii penetrates virtually any kind of mammalian cell using proteins released from late secretory organelles and a unique form of gliding motility. How T. gondii glycosylated proteins mediate host-parasite interactions remains elusive. Here, we report comprehensive proteomics and glycomics analyses showing that several key components required for interactions between T. gondii and host cells are N-glycosylated. Detailed structural characterization confirmed that N-glycans from T. gondii total protein extracts consist of oligomannosidic and paucimannosidic sugars, which are rarely present on mature eukaryotic glycoproteins. In situ fluorescence using concanavalin A and Pisum sativum agglutinin predominantly stained the entire parasite body. Visualization of Toxoplasma glycoproteins purified by affinity chromatography identified components involved in gliding motility, moving junction, and other additional functions. Importantly, tunicamycin-treated parasites were considerably reduced in motility, host cell invasion, and growth. In addition, we show that all three potential N-glycosylated sites of GAP50 are occupied by unusual N-glycan structures with terminal glucoses. Using site-directed mutagenesis, we demonstrate that N-glycosylation is a prerequisite for GAP50 transport into the inner membrane complex. Assembly of key partners into gliding complex by unglycosylated GAP50 and parasite motility are severely impaired. Collectively, these results provide the first molecular description of T. gondii N-glycosylation functions that are vital for parasite motility and host cell entry
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Constantino, Maira Alves. "Investigating effects of morphology and flagella dynamics on swimming kinematics of different helicobacter species using single-cell imaging." Thesis, 2017. https://hdl.handle.net/2144/27383.
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This work explores the effects of body shape and configuration of flagella on motility of Helicobacter pylori, a helical-shaped bacterium that inhabits the viscoelastic gastric mucosa and causes gastritis, ulcers and gastric cancer. Although it is well known that different shapes produce different hydrodynamic drag thus altering the speed and that helical shapes generate additional thrust this has not been quantitatively established for flagellated bacteria. Using fast time-resolution and high-magnification two-dimensional phase-contrast microscopy to simultaneously image and track individual H. pylori and its rod-shaped isogenic mutant in broth and mucin solutions, the shape as well as rotational and translational speed was determined. In collaboration with Professor Henry Fu and Mehdi Jabbarzadeh the experimental data was used to validate the method of regularized Stokeslets by directly comparing the observed speeds to numerical calculations. The results show that due to relatively slow body rotation rates, the helical shape makes at most a 15% contribution to speeds. In order to explore the effects of arrangement of flagella on motility three different Helicobacter spp. were examined: H. suis (bipolar, multiple flagella), H. cetorum (bipolar, single flagellum) and H. pylori (unipolar, multiple flagella) swimming in broth and mucin. Results show that regardless of media, the flagella bundles of bipolar bacteria can assume one of two configurations interchangeably: extended away from the body or wrapped around it. H. suis predominantly swims with the lagging flagella extended behind the body and the leading flagella wrapped around it, but cases where both bundles are extended or both are wrapped have also been observed. In addition the effects of varying pH on motility of H. suis in broth and mucin were investigated. In broth the rotational speed is not significantly affected by varying pH and the peak of the speed distribution shifts to lower values as the pH decreases. However in mucin the rotational speed decreases by a factor of 20 from pH5 to 4 and the motion is completely hindered below pH4. This indicates that H. suis is unable to move below pH4, in agreement with previous findings on H. pylori, due to gelation of mucin below pH4.
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Tout, Jessica Alyce. "Exploring the function and behaviour of natural populations of coral reef microbes." Thesis, 2016. http://hdl.handle.net/10453/43503.
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University of Technology Sydney. Faculty of Science.Microorganisms live in tight associations with corals, but the ecological interactions and microbial functions and behaviours underpinning these relationships are not yet fully understood. The goal of this thesis is to define coral-microbe interactions by exploring how the composition, behaviour and function of microbial communities vary throughout a coral reef and how increasing sea water temperatures can affect coral-microbial relationships. As a first step to achieving this aim, In Chapter 1 we used metagenomics to characterise patterns in microbial composition and metabolic capacity across different niches, including coral-associated and non-coral associated microenvironments, on Heron Island, the Great Barrier Reef (GBR). We found that the composition and metabolic potential of coral reef bacteria is highly heterogeneous across a coral reef ecosystem, with a shift from an oligotrophy-dominated community (e.g. SAR11, Prochlorococcus, Synechococcus) in the open water and sandy substrate niches, to a community characterised by an increased frequency of copiotrophic bacteria (e.g. Vibrio, Pseudoalteromonas, Alteromonas) in the coral seawater niches. Among the major functional patterns observed were significant increases in genes associated with bacterial motility and chemotaxis in samples associated with the surfaces of coral colonies. The observation of increased motility and chemotaxis near to coral surfaces is notable given previous evidence that these phenotypes may be involved in coral disease processes. The research presented in this chapter was published in Microbial Ecology (2014 67 (3): 540-552) To investigate these patterns in chemotaxis further we next (Chapter 2) directly examined the potential ecological role of chemotaxis among coral-associated bacteria, by using laboratory based and in situ chemotaxis assays to test levels of chemotaxis among natural communities of coral reef microbes. We examined the behavioural responses towards several chemoattractants known to be released by corals and their symbiotic dinoflagelletes including amino acids, carbohydrates, ammonium chloride, and dimethylsulfonopropionate (DMSP). Using these approaches we found that bacteria associated with the surfaces of the corals exhibited high levels of chemotaxis, particularly towards DMSP and several amino acids. Levels of chemotaxis by coral-associated bacteria were consistently higher than those demonstrated by non-coral associated bacteria. This work was published in the ISME Journal (doi: 10.1038/ismej.2014.261) We next extended the in situ chemotaxis assays to examine the chemotactic behaviour of bacteria associated with other important coral reef organisms, sponges. These results redefine the sponge-symbiont acquisition paradigm whereby we show for that bacteria use chemotaxis to locate their sponge host on a coral reef. This work is in preparation for submission to the ISME Journal. After defining some of the functions and behaviours involved in coral reef microbiology, we next examined how these processes may shift under changing environmental conditions, associated with climate change. To determine how environmental variability, specifically thermal stress, influences bacterial community composition, behaviour and metabolic capacity, manipulation experiments were conducted using the coral Pocillopora damicornis. To investigate the dynamics of coral-associated vibrios under heat stress, in Chapter 4 we used Vibrio-specific amplicon sequencing approaches and qPCR to quantify shifts in the abundance and composition of natural populations of Vibrio, with a specific focus on the putative coral pathogen V. coralliilyticus. These experiments revealed that increasing seawater temperatures can favour the proliferation of potential coral pathogens among a natural mixed microbial community. This work has been published in Frontiers in Microbiology (6:432.doi: 10.3389/fmicb.2015.00432). In Chapter 5, we decided to explore the entire coral-associated community by using metagenomics and metatranscriptomics to investigate how the phylogeny and function of coral associated microbes shift resulting from increasing seawater temperatures. We found a dramatic shift in the community from Endozoicomonaceae being dominant in the control corals, while there was an appearance of the vibrios under increasing sea water temperatures in line with our findings from chapter 4. We also observed functional shifts that involved an upregulation of chemotaxis and motility genes at higher temperatures and were shown to be affiliated with vibrios, a genus which contains several putative coral pathogens. Taken together our data demonstrate that coral reef bacterial communities are highly dynamic and that key groups of copiotrophic bacteria have the capacity to use behaviours such as chemotaxis to use nutrient gradients to potentially locate and colonize benthic host animals including corals and sponges. Increasing seawater temperatures causes dramatic changes in the coral-associated bacterial community, allowing for the proliferation of potential coral pathogens and increased expression of behavioural phenotypes that may promote successful infection of corals.
Books on the topic "Microorganisms – Motility"
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NATO Advanced Study Institute on Biophysics of Photoreceptors and Photomovements in Microorganisms (1990 Tirrenia, Italy). Biophysics of photoreceptors and photomovements in microorganisms. New York: Plenum Press, 1991.
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Aharon Katzir-Katchalsky Conference on "Sensing and Response in Microorganisms" (1985 Weizmann Institute of Science and Kibbutz Ayelet Hashahar). Sensing and response in microorganisms. Amsterdam: Elsevier Science Publishers, 1985.
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Michael, Eisenbach, Balaban Miriam, and Aharon Katzir-Katchalsky Conference on the "Sensing and Response in Microorganisms" (1985 : Weizmann Institute of Science and Kibbutz Ayelet Hashahar), eds. Sensing and response in microorganisms. Amsterdam: Elsevier Science Publishers, 1985.
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(Editor), F. Lenci, Francesco Ghetti (Editor), Giuliano Colombetti (Editor), D. P. Häder (Editor), and Pill-Soon Song (Editor), eds. Biophysics of Photoreceptors and Photomovements in Microorganisms (Nato Science Series: A:). Springer, 1991.
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E. coli in Motion (Biological and Medical Physics, Biomedical Engineering). Springer, 2003.
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W, Alt, and Hoffmann G, eds. Biological motion: Proceedings of a workshop held in Königswinter, Germany, March 16-19, 1989. Berlin: Springer-Verlag, 1990.
Find full textConference papers on the topic "Microorganisms – Motility"
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Scherr, Thomas F., Chunliang Wu, W. Todd Monroe, and Krishnaswamy Nandakumar. "Numerical Simulation of Cell Motility at Low Reynolds Number." In ASME 2012 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/sbc2012-80280.
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As length scales decrease to microns, the mechanism for swimming becomes unfortunately counter-intuitive. In the macro-world, where human intuition has developed, we swim by accelerating the liquid around us. For microorganisms, which swim at Reynolds numbers much less than unity, Stokes law does not permit accelerations. As such, the fluid movement is governed entirely by the local boundaries of the microorganism and the fluid viscosity dampens velocity fluctuations rapidly as distance away from the swimmer increases. A well known byproduct of this, Purcell’s “Scallop Theorem”, forbids reciprocal motions to generate net forward movement [1]. To overcome this, flagella propagate waves down their length and cilia have asymmetric beats. This type of motility has been described as zero-thrust swimming since the net force on the organism-fluid system must be zero [2].
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Fadlallah, Hadi, Hassan Peerhossaini, Christopher De Groot, and Mojtaba Jarrahi. "Motility Response to Hydrodynamic Stress During the Growth Cycle in Active Fluid Suspensions." In ASME 2020 Fluids Engineering Division Summer Meeting collocated with the ASME 2020 Heat Transfer Summer Conference and the ASME 2020 18th International Conference on Nanochannels, Microchannels, and Minichannels. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/fedsm2020-20125.
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Abstract In this work, we focus on the motility behavior of two model microorganisms widely used in the study of active fluids: Chlamydomonas reinhardtii microalga and Synechocystis sp. Cyanobacterium. Understanding the physiological responses of microorganisms under variable environmental conditions is essential for bioreactor engineering. Yet, most of the previous studies focused on the observation of cellular motility regardless of the growth process. Here, we measure the motility of Chlamydomonas reinhardtii and Synechocystis sp. during their growth when subjected to different intensities of hydrodynamic shear stress. The results demonstrate a significant difference in the motility response of the two species against the applied hydrodynamic shear stress. Mechanical agitation appears to affect the motility of Chlamydomonas reinhardtii microalgae by stimulating the growth process and increasing the magnitude of the cellular swimming velocity. The motility varies following 3 different phases: the rising phase starting almost at the middle of the exponential growth phase, and the decay and damped phases during the stationary phase. This behavior is described using a linear model for the rising phase and a damped oscillatory model for the decay and damped phases. The motility of Synechocystis does not follow a well-defined pattern in time. However, it seems that the peak of the swimming velocity occurs always in the middle of exponential phase of growth. Synechocystis cells show a high endurance to the applied shear such that the global effect of agitation intensity on their motility is insignificant.
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"Motility and fitness of microorganisms in dynamic aquatic ecosystems: a simulation study." In Bioinformatics of Genome Regulation and Structure/ Systems Biology. institute of cytology and genetics siberian branch of the russian academy of science, Novosibirsk State University, 2020. http://dx.doi.org/10.18699/bgrs/sb-2020-100.
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Iungin, Olga, Ievgeniia Prekrasna, Ihor Bortyanuy, Valeriia Maslak, and Saulius Mickevičius. "Plant Growth-Promoting Characteristics of Antarctic Endophytic Bacteria." In The 9th International Conference on Advanced Materials and Systems. INCDTP - Leather and Footwear Research Institute (ICPI), Bucharest, Romania, 2022. http://dx.doi.org/10.24264/icams-2022.ii.11.
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The work is focused on studying bacteria associated with vascular plants in Antarctic region. Climate changes affecting the Antarctic Peninsula favor the successful colonization of ice-free lands by two Antarctic vascular plants (Deschampsia antarctica and Colobanthus quitensis). Bacteria isolated from D. antarctica collected during the 25th Ukrainian Antarctic Expedition (January-April 2020) along the Western part of the Antarctic Peninsula were studied for plant growth-promoting characteristics (nitrogen fixation, phosphate solubilization, cyclic lipopeptide production, exoprotease production, motility and carbohydrate utilization). The heterotrophy of bacterial isolated from D. antarctica and the presence of a wide range of saccharolytic enzymes for the utilization of mono- and disaccharides in studied cultures were shown. This may indicate the plasticity of metabolism and the high adaptation potential of microorganisms associated with D. antarctica. PGPT of studied bacteria were mostly presented by nitrogen-fixing ability and cyclic lipopeptides synthesis.
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Kizghin, Dilziba, Sangjin Ryu, Younggil Park, and Sunghwan Jung. "Swimming of the Trophont Zooid of Vorticella Convallaria." In ASME 2021 Fluids Engineering Division Summer Meeting. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/fedsm2021-63265.
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Abstract Vorticella convallaria is a ciliated protozoan found in freshwater habitats. In the sessile or stalked trophont form, V. convallaria is shaped somewhat like a balloon as it has a body or zooid (the head of the balloon) that is about 40 μm large with cilia around its oral part, and a stalk (the string of a balloon) anchoring the zooid to a solid surface. When a trophont zooid of V. convallaria detached from the stalk, the zooid swims around in water by creating water flow using its oral cilia. In contrast to the stalk contraction of V. convallaria that has been well studied, the swimming motility of V. convallaria is little known. In this study, we measured the swimming trajectories of the stalkless trophont zooid of V. convallaria using video microscopy and Hele-Shaw cells with a gap height of 25 μm, traced the swimming zooid using image processing, and analyzed the swimming motion in terms of swimming velocity and mean square displacement. The stalkless trophont zooid of V . convallaria was found to swim in circular patterns with intermittent ballistic motions in the confinement, and the average swimming speed ranged from 20 μm/s to 110 μm/s. Since the swimming pattern of V. convallaria appeared to be affected by the level of confinement, we will continue characterizing the ciliate’s swimming in the Hele-Shaw cell with different gap heights. Our study is expected to reveal the swimming motility of V. convallaria and to advance general understanding of swimming of microorganisms.
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Samadi, Zahra, Malihe Mehdizadeh Allaf, Thomas Vourc'h, Christopher T. DeGroot, and Hassan Peerhossaini. "Are Active Fluids Age-Dependent?" In ASME 2022 Fluids Engineering Division Summer Meeting. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/fedsm2022-87914.
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Abstract Active fluids are often is known as the aqueous suspensions of self-propelled elements such as bacteria, algae, or sperm cells, which their properties fundamentally differ from conventional fluids. Active fluids exhibit remarkable physical manifestations over a wide range of scales, from time-dependent microscopic diffusion to the large-scale colonization of aqueous spaces. Properties of active fluids depend on the behavior of microbial suspensions, among which motility plays a crucial role. In this work, we focus on the effect of microbial growth and aging on microorganism motility. Hence, the motility behavior of cyanobacterium Synechocystis sp. CPCC 534, and its relationship with aging were investigated in a closed microfluidic chip. The growth of Synechocystis cultures was followed from the lag phase, through exponential and linear growth up to the stationary phase. Culture samples were periodically examined; cell populations were measured by spectroscopy technique and cell trajectories were tracked by video-microscopy. Cell trajectory length and average cell motility were extracted from the video recordings and were correlated with the age and growth phase of the bacterium.